Cam-shaft drive.



E. BUGATTI. CAM SHAFT DRIVE.

Af'PLIOATION FILED APR.20,1914.

LELQQJQFK v Patented. Jan. 5, 1915.

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Spegificetion ofletters latent.

@FFEQE Patented Jan, 5, 1915,

Application filed A ril 20, 1914. Serial Nc.'833,1.74.

To all whom it may concern i Be it known that 1, Errors; BUcA'rrI, a subject of the King of Italy, and residing at Molsheiin, Alsace, German Empire, have 1 invented certain new and useful Improvements in Cam-Shaft Drives, of which the following is a specification.

The present invention has reference to improvements in cam-shaft drives and relates more specifically to mechanism for driving cam shafts or the like, which are acted on in quick succession by oppositely directed forces, as 1s the case tor lnstance in autombile and the like engines with camdriven push rods for the valves, and the particular object of the invention is to pr'ovlde means whereby the rattling or clapper ing noise, now found in such devices, is coinpletely done away withl In cam-shafts that are driven by spur' gearing there is often heard a disagreeable, continuous rattling, due to the action of the valve springs, which on the valve orvalves having exceeded the highest position, cause a sudden forward drive or jumping-ahead of the cam-shaft with corresponding acceleration of the spur wheel fast on this shaft,

with the result that the then driving faces of the teeth of this cam-shaft wheel hit against the opposing rear faces of the teeth of the driving spur proper, fast on the crank-shaft. I

According to this invention the rattling noise is ellectively suppressed and the drive made practically noiseless by placing the driven wheel under the continuous action of a braking or retarding mechanism, which prevents sudden accelerations of "the camshaft wheel and causes the respective flanks of the spur-wheelteeth to remainiiinv permanent operative contact. I

The nature of this invention will: best be understood when described in connection with the accompanying drawings, in which- 1*igure 1 shows a vertical section through the improvement, partly in elevation. igs. 2 and 3 shows fragmental side elevations of the spur gearings. A To the crank-shaft a are fixed the toothed wheels 7), c, of which the wheel 6 is of slightly. larger diameter than the wheel 0. These wheels mesh with toothed wheels 6 and d'"'of correspondingly different diameters, of which the larger wheel 6 is loose and the smaller wheel (Z fast on the cam-shaft f. Both Wheels e, cl are secured against axial displacement on the cam-shaft, as are also the wheels I), 0. Upon rotation of the crankshaft the two pairs of wheels D, (Z and c, e

rotate, the wheel (Z soon outstripping the wheel 6. The: two camshaft wheels 6, d are elastically interconnected by an adjustable friction coupling, which comprises a conically tapering coupling annulus g,

which is axially displaceable on suitable' supports, as shown on screw studs it. These latter are secured in the wheel 6 and carry the volute springs By more or less tightening these springs the pressure with which vthe friction annulus is forced against the correspondingly profiled, dished wheel' d can be varied. Upon rotation of the cranlo' shaft or with the spur-wheels b, '0 in the di rection of thevarrow 1, the fixed wheel d is driven in the sense of arrow 2, the respec- 5 tive wheel teeth flanks touching as shown in Fig. 2. Owing to the interposed friction coupling the wheel e. whose number of rev- "'ollutions is smaller than that of the wheel at} will be dragged along by thelatter, as it w .re; and the wheel 6 will in turn drive the wheel 0, fast on the crank shaft a, as far as the resistance of, the friction couplingallows of this, the teeth of the spur wheels 6 Iii this cooperation of the 'spur gears and coupling, the wheel 6 cannot follow the wheel d with the same speed, but is steadily retarded to some extent by the wheel 0. in

consequence there is set up a certain, barely perceptible slipping between wheel (Z and the coupling annulus g, which slippa'ge is used to act as means for continuously braking (retarding) the wheel (Z. As a result the cam-shaft is prevented fron suddenly jumping-ahead upon the push-rods I; pass- .ing the highest points of the camsfjl, andthe cause for the rattling in the valve gear is eilectively' eliminated.

hat I claim is 1. In a cam-shaft drive of the character described, a crank-shaft, two toothed wheels" of different diameters fast thereon,a camshaft, a toothed wheel loose thereon and mesh ngniith the said smaller crankshaft wheel, a tootlied---wheel fast on saidcamshaft and meshing with said la-rgenprankshaft wheel, and an elastic coupling between the said two camshaft wheels.

2. In a cam-shaft drive of the character 1.19 described, in combination, a crank-shaft, a I

toothed wheel fast thereon, a second toothed ndc then. contacting as. shown in F f, 35

wheel eiongsicie thereof, also fast, on s ekif oi'mfik-sheft-and of somewhat larger (flamesez' iimn the first said toothed "wheel; a cam :i toothed wheel loose thereon am meshing with the first said crank-shaft Wheel, a'seoond toothed wheel fast on said cam-shaft, oi' somewhat srosliei' diameier than the first said cam-shaft wheel anci meshing with said iaiger crank-shaft wheel; and a drag coupling device interposed between the said iwo min-shaft .vheels, comprising a, friction onnuius oni'ried by one of one letter WilQEiS, and edjusiable means for keeping said annulus pressed more 01' less firmly against the respective other whee}.

3. In 2; com-shaft drive of the character desoziheoi, in combination, a crank-shaft, a tootheci wheel fest thereon, a second toothed Wheel fusion said orank-slmft and of somewhat larger diameter than the first said toothed Wheel; e camshaft, o toothed Wheel loose thereon and meshing with the smaller memo? obie means for regulating the operative friction pressure of seid annulus against said dishecl cam-simft Wheel.

In testimon whereof I aiiix my signature in presence of two Witnesses.

ETTO RE BU GATT. Q.

Witnesses:

Josmw Roman, CHARLES A. HALLEY, Jr. 

